1. Field of the Invention
The present invention relates to a parts assembly method and the equipment to carry out the method, for assembling parts or components such as instrument parts in a structure member such as an instrument panel, and especially a parts assembly method and device which is able to automatically assemble the parts or components in a reliable manner.
2. Description of the Prior Art
Usually, in an assembly line such as those for automobiles, the instrument to be assembled in an automobile is made up by assembling various kinds of parts or components in an instrument panel used as a receiving member or structure member. A production line system is usually adopted for making up these instruments in consideration of its effective operation. In this type of conventional parts assembly method, the instrument panel is set in a fixed position in a fixture mounted on a conveyor, and the instrument panel is transported by means of the conveyor to an assembly stage. Then, each part is assembled in sequence, by manual operation, into the transported instrument panel at the assembly stage.
This method of assembly, using manual labor, is very inefficient, and consequently the need for automatic assembly has become very pronounced.
Accordingly, automatic equipment such as robots is provided for conventional parts assembly devices at each stage of the assembly, and these robots carry out the parts assembly operation through teaching data prepared in advance.
However, in this type of conventional parts assembly method, the instrument panel having a plurality of mounting portions for receiving parts or components is maintained in a fixed attitude on the conveyor to transport it. For this reason, the mounting portions provided for receiving the parts or components in the instrument panel face in different directions. In this case, when the parts or components are inserted into or mounted to the mounting portions in the instrument panel, their access direction must correspond to the direction in which each mounting portion faces. For this reason, it is necessary to have many multishaft robots which are capable of complicated movements to assemble such parts. Therefore, the cost of the parts assembly device itself becomes very large, and depending on the assembly direction, poor assembly can result from displacement of the part or component caused when screws are being tightened to secure the part or component in place. In addition, it could become impossible to carry out assembly, as a result of problems with the shape of the instrument panel and the space available when the parts or components are inserted and the screws tightened, if interference develops between the instrument panel and the robot arm or the screw tightening device.